Laser-welded crane rail for suspended crabs

Abstract

Disclosed is a crane rail made from a roll-formed steel sheet strip. Said crane rail altogether comprises a top flange and a bottom flange. A support flange that has a triangular cross-section is additionally embodied on the top flange. The edges of the steel strip are laser-welded to the web.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This patent application is the national phase of PCT / EP2007 / 009684, filed Nov. 8, 2007, which claims the benefit of German Patent Application No. 102006054682.2, filed Nov. 17, 2006.FIELD OF THE INVENTION[0002]The present invention relates generally to crane rails for suspended crabs.BACKGROUND OF THE INVENTION[0003]Travel rails for suspended crabs are made from roll-formed sheet steel for cost and weight reasons. One example of such a travel rail is described in DE 41 19 868 A1. The rail forms a hollow bottom flange and a hollow top flange that are connected to one another by a web. The web is configured as a single piece with one-half of the hollow top flange and one-half of the hollow bottom flange situated thereunder. The other halves of the top flange and the bottom flange consist of two individual roll-formed sheets that are then correctly positioned and joined to the part containing the web. These parts are then welded together.[00...

AI Technical Summary

Benefits of technology

[0005]In view of the foregoing, a general object of the present invention is to develop a rail with superior properties that can be manufactured more simply.

[0006]The inventive rail consists of a single piece of roll-formed steel strip such that the handling of several parts is eliminated. After the roll-forming of the single sheet steel strip, the bending of the complete rail is finished. Devices for holding together any other parts in the correct position are not required. The handling during the welding process is also simplified because it is not required to join any long parts that are susceptible to bending for the welding process.

[0007]In addition, the steel strip edges of the new travel rail are laser-welded. Very little heat is introduced during the laser welding process such that practically no welding distortion can occur. Laser-welded seams are furthermore very reliable with respect to their strength behavior. Laser-welded seams also can be reproduced very well.

[0010]Due to the design of the rail profile, the bottom flange may be free of welding seams. The bottom flange may have a rectangular cross-sectional profile, where the height may lie between 10 mm and 30 mm. The bottom flange may have a width between 50 mm and 80 mm. If the profile is configured in this manner, the top flange may be free of welding seams, which favorably affects the handling, as well as the subsequent stability.

[0013]If designed according to the invention, the web that connects the top flange to the bottom flange may be largely realized with two layers. The laser welding seams preferably lie in regions, in which a low stress occurs during the subsequent use. It may also be advantageous if the web respectively consists of two layers in two strip-shaped regions that border the top flange and the bottom flange and only one layer in between. This creates space for welding the steel strip edges to the continuous section of the web to produce an integrally connected part, although the starting material featured two edges that were not connected to one another.

Problems solved by technology

The welding costs are relatively high since, during the welding process, the parts must be correctly positioned and fixed in place by means of corresponding devices.

Furthermore, the welding seams are located where there is a risk of welding distortions.

It is particularly difficult to produce long, reliable MAG welding seams on relatively thin material.

Due to its shape, the rail is also susceptible to bending during transport and has a low torsional rigidity.

Images